Steam heating circulation system



May 26, 1953 a. c. SKINNER STEAM HEATING CIRCULATION SYSTEM Filed Jan. 7} 1948 Patented May 26, 1953 STEAM HEATING CIRCULATION SYSTEM Bronson C. Skinner, Dunedin, Fla., assignor to Clinton Foods Inc., New York, N. Y., a corporation of Delaware Application January 7, 1948, Serial No. 1,047

13 Claims. (01. 237-9) The present invention relates to steam heating circulation systems designed to provide steam heat for various types of heat exchange equipment, such as steam kettles, steam dryers, etc.

A general object of the present invention is the provision of such a system which is readily and relatively inexpensively constructed and economically operated and maintained, characterized by means to provide the major portion of the steam demands at relatively low pressure and condensate return to a receiver wherein condensate and flash steam are separated from each other. The condensate is suitably drained off at the receiver with the flash steam being economically recirculated by a small jet booster effectively operated by a very minor fraction of steam demand at relatively high pressure. Consequently, necessity for using expensive large and complex injectors and appreciable power consuming and costly pumps is avoided.

A more specific object of the present invention is to provide in such a system simple and inexpensive jet booster means connected between the main steam demand supply from any suitable source, such as the exhaust of steam-operated mechanism, and the condensate receiver to create a differential in pressure eifectively to draw off from the latter flash steam and conservatively return it to the heat exchange equipment, with the employment for jet operation of high pressure steam in very small quantity of the order of a few percent or less of the total steam demand.

Another object of the present invention is the provision in such a system of a receiver-tank so constructed as to receive therein from a return line a mixture of steam and condensate, and efiiciently to separate those fluids, permitting effective drainage of the condensate and feed of flash steam back into the system, both from the receiver tank.

A further object of the present invention is to provide structural embodiments of the invention which are readily constructed and permit efficient use and operation thereof.

Other objects of the invention will in part be obvious and will in part appear hereinafter.

The invention accordingly comprises the features of construction, combination of elements,

and arrangements of parts, which will be exemplified in the construction hereinafter set forth,

and the scope of the invention will be indicated in the claims. a

For a fuller understanding of the nature-and objects of the invention, reference should be had 2 to the following detailed description taken in connection with the accompanying drawing, in which:

Fig. 1 is a side elevational view, partly in section and with parts broken away, of an embodiment of the steam heating circulation system of the present invention;

Fig. 2 is an enlarged elevational section of an air-venting thermostatic valve preferably employed in the apparatus shown in Fig. 1; and- Fig. 3 is an elevational section of a modified form of the condensate receiver shown in Fig. 1.

Referring to the drawings, like numerals identify similar parts throughout and, as will be seen from Fig. 1, an embodiment of the present invention may comprise a plurality of steam kettles I0, Iii of known construction, each preferably consisting of an inner copper material-receiving pot II and an outer shell 12, providing therebetween a steam space I3, which constitutes a steam passage through that heat ex change equipment. A steam source is represented by the supply main M, which may be connected to any suitable steam generating equipment to provide steam at relatively high pressure, such as one hundred and twenty-five pounds (125 lbs.) gauge. The steam main H has therein a manual shut-offvalve l5 and a constant pressure regulating or reducing valve [6, of known construction. Beyond the pressure reducin valve l6, suitable piping constitutes the main supply pipe means for feeding the major amount of the steam demand to the heat exchange equipment and may comprise feeder pipe 1'! connected by a T-fitting [8 to a pipe [9 which is equipped with T-fittings 2020 to supply steam via branch pipes 2l- -2l to the steam spaces [3, it of steam kettles l0, l0. Preferably pipe I9 is provided with a safety relief valve 22, of known construction.

, Since constant pressure regulating or reducing valves generally comprise a valve operated by a piston, diaphragm, or other equivalent means, responsive to pressure at the point where constant pressure is desired, the pressure reducing valve It is connected by a pipe 23 to one of the branch pipes 2| which leads to the steam space 13 of one of the steam kettles l0. In a particular setup, it may be desired to operate the steam kettles l0, 10 at a steam load of about five thousand pounds per hour (5,000 lbs/hr.) at about forty-five pounds (45 lbs.) gauge. Proper setting of the constant pressure reducing valve It will maintain these desired conditions with steam being supplied through the main M at 3 about one hundred and twenty-five pounds (125 lbs.) gauge.

The steam space 33 of each steam kettle In is connected by a drain pipe to a suitable condensate return pipe and, as shown in Fig. 1, drain pipe 24 of one kettle is longer than drain pipe 25 of the other kettle, so that the condensate return pipe 26 can be. sloped downwardly for gravity flow of condensate water to a receiver 27. In the system of the present invention, means are provided to create suction on the receiver 2?; so that the return pipe will keep the steam spaces it freely drained. It has been a practice to employ thermostatic traps in. drain lines of such heat exchange equipment vrhich'require cooling of condensate to a temperature of about ten to thirty degrees (1 9 309) F. before such traps will open, and, as a result, there 'is a tendency for the traps to back up the condensate water and air or other non-condensible gases into the steel? spaces of the kettles, therebycovering, or blanketing a part. of the surface oj the pot thereof and reducing the efiiciency of the settlement. With suitable suction imposed on receiver and with the condensate return line and its drain pipes 3c and 25 being unobe structed, and with the condensate return sloped downwardly, as. proposed in E i-;. 1 provision is made for free flow at all times; for condensate waterand exhaust steam. It. will be: understood, however, that return line it need not, be sloped downwardly towards receiver El, since. if it were substantially horizontal, suction imposed on the receiver would cause suitable flow of condensate am} steam to, the receiver.

The receiver 2t may comprise a closedtank appreciable having. a top 29 andv a bottom 3%. Through the side of the tank; 2-8 is. let a. 31: adapted to. bringthe condensate ijteturn pipe 2% into communication with the in: terior otthe receiver tank 23,. thus providing; an inlet at a point which is appreciably below the. top into. a space. of appreciable volume.

Bottom or receiver tank 25 provides a contlensate collecting;- space or some has upper limit 33. Suitable drainage. means, staples/iced as an outlet for the condensate. col.- lection zone or body of water 35 therein, and comprise a hollow casting 236 connected by a passage. it! to. the interior of the tan 2.2; and

provided with a drain pipe 38, which may lead to. sewer or, to steam generating equipment for sup.- ply of; steam main I l, as may be desired.

The upper limit or the maximum height 3.3. of the surface or condensate 35 in the bottom of the. tanlc E8 is predetermi'i-ied' by an suitable automatic valve mmns, suchas a float valve in castcperateel bya heat as, all or"- known construction, which controls out-flow of the Water through the passage 3'? intothe drain pipe 38.

A fitting tilt in the. top; 28: of tank- 28 provides outlet for flash steam from the steam space or zone i l-2 0i. the receiver and brings. the late ter into,- coznm-unicaltion with. conduit means. or

pipe: 4.5., which has a. manual valve izztherein and is connected to. a small jet booster 33 or the. ir1.-. jectol: type. The outlet side of jet booster. 43 is connected by means, of a pipe as, having a. manualvalve lhtherein, to the T-fitting ills, anclthns. to. the. main supply pipe means comprising pipes l 7 and I9, and branch pipes 2l--2l..

The. small jetv booster 13 is of known construction. and. comprises a hollow casing; 46- haying. a, constricted outlet. 41 1 connected to: pipe. M and an inlet. til. connected toconduit- M. The. jet

4 booster 43 includes the usual nozzle 39, which is connected to a suitable source of relatively high pressure steam by means of feed pipe :"lii. It is shown in Fig. 1 that feed pipe 59 may lead through a manual valve 5| to connection at 52 with the relatively high pressure main Hi. However, should it be desired to connect main 4 to a relatively low pressure source of steam, such as the exhaust of a steam turbine, at a pressure of about forty to forty-five pounds (-lO- lbs.) gauge, a relatively small separate source of relatively high-pressure steam may be provided for jet booster 43. For this purpose, nozzle feed pipe 'llmay be. arranged-to be connected directly to the soparatesoure of relatively high pressure steam.

Itis desired to vent air from the system at the receiver 2'1. An air-venting tube 55 is provided with its. intake end as located above but in the near vicinity of the maximum height of the condensate suriaceor the top or the zone at. 313.. Von-t. tube 515 is prefe ably connected through suitable valve means 55? the drainage casting, 3&- and', where drainage pipe as is connectedato sewer, outletv 58 of valve may-extend clown to, spill into drain pipe 3.8, as. indicated in dotted lines in Eig,. L.

Preferably, the air-venting, valve 257i. is: a thermostaticvalve, as. shown in-E-ig'. 2, comprising; a hollow casing as having an externally-threaded. nipple. ill for connection. by means of an internal-ly-threaded collar tovent 55 and prov-iding an. inlet passage 62-, Another externall-yr-- threaded nipple 53 is adaptedforscrew-threaded; engagement in an internally-threaded holein; casting; to and, together with spill pipe 58', pr c an outlet. passage Ma. Cap. 65' closes: off the top of the. hollow; casing llll and a. thermany-expansive bellows ca, having on; the. bot.- tom end thereof a. valve E 'ltoclose cit the out-- let passage Ell. Thermally-expansive bellows. 66 is of such characteristics. as to hold the valve: 6.1 in the open position shown in. 2- when air fills zone or space 514,, but when substantially or; the air is vented. from, zoneor space Ei l and steam. tends to fil-lt that space and; to flow out. vent. tube 55- its higher temperature will; cause extension of the bellows t6; to close the; outlet 6 3i and prevent uneconomical bleeding; or loss of flashsteam. It it is desired: to: connect the; drain pipe; 38 to; steam generating: equipment, or course the outlet passage Gi -may be connected via a.

bore in casting 38 directly to the atmosphere.

Suitable ba-fiie means are: provided in. the vicinity of the end Shot thetube: 55,- to; avoid ad;-

mixingair in the. zone 54;. with flashsteamas exhaust steam. and condensate are spilled. trom return, line. 2.6 into; the. tank 2-8,. For this. purpose the baiiie. means, comprise a. partitiomg. plate. (it, having about thirtyto. forty (Bil-410; holes therein, each of about one halt. iarrchzt in: diameter and: located below the:ilil18l3.'13ll0.\lldd Icy-fitting; 3t, preferably immediately below the latter.

A variety of typess'ofi bafileemeansmay be.- used: it might. comprise a, plurality of? staggerecl plates. [liar-L68 which. have their: free. edges spaced apart and overlapped to provide a tortuous passag down to the. zones. 3.5. and 5/35.; Eris; merely necessarythat; such bafille. means be pervious. toe.,, admit passage. oii-such therethrough while mufiling or damping out: swirling: currents and slowinailm. flow; tcr minimize turbulence. v

In operation of the system shown in Fig. 1, it may be assumed that the steam kettles I0, 10 are to be operated at a steam pressure of about forty-five pounds (45 lbs.) gauge in the steam spaces l3, l3 with a consumption of about five thousand pounds (5,000 lbs.) of steam per hour and with the main I4 connected for that purpose to a steam source at about one hundred and twentyfive pounds (125 lbs.) gauge pressure. The small jet booster 43 will be of such capacity as to handle about fifty pounds per hour (50 lbs/hr.) at about one hundred and twenty-five pounds (125 lbs.) gauge pressure through its nozzle 49. With the manual valves [5, 42, 45 and all closed, operation of the system may be initiated by opening valve [5 so as to supply steam to kettles H1, H1 through pressure reducing valve It at a pressure of about forty-five pounds (45 lbs.) gauge which will be efiiciently maintained by the pressure reducing valve. During heat transfer in kettles I0, steam is condensed and the condensate flows by gravity with exhaust steam down the drain pipes 24 and 25 to the condensate return line 26 and thence to the receiver 2'1. As the exhaust steam and condensate are spilled from the fitting 3| into the tank 28, the water will flow downwardly through the bailie means or perforated plate 68 and collect in the zone 35. The body of condensate 35 gradually increases in volume raising drainage valve operating fioat 39 until the drainage valve is opened to permit flow of water out of drain pipe 38. Air above the surface of the condensate is vented to atmosphere via vent tube 55 and thermostatic valve 57.

Now if full operation of the system is brought about by opening valves 42, 45 and 5|, a minor fraction of the steam demand, say, about one percent (1%), will be supplied at relatively high pressure, say, one hundred and twenty-five pounds (125 lbs.) gauge, through branch line 50 to the jet booster nozzle 49, which will handle about fifty pounds per hour (50 1bS./h1'.). The resultant suction created through conduit 4| on the interior of receiver tank 28 causes an immediate drop of the pressure in the tank 28 to about thirty-eight pounds (38 lbs.) gauge with an attendant differential in pressure of the order of about seven pounds ('7 lbs.) gauge. This suction rapidly withdraws flash steam from zone 32 in receiver 21 at the rate of about fifty pounds per hour (50 lbs/hr.) and feeds it back into the system for recirculation while causing a very rapid and free flow of condensate and exhaust steam from the kettles l0, 10 through the unobstructed drain pipes 24 and 25 and return line 26 to the receiver 21. Thus eflicient operation is attained with the steam kettles ID, ID being freed at all times for condensate and with flash steam being fed back into the system for re-use, with little wastage of the latter and with a small percentage of high pressure steam utilized to operate the jet booster 43. High efficiency in operating cost is attained with minimum losses other than those represented by minor heat and frictional losses and without the necessity of employing power-operated circulating pumps or expensive, complicated injectors through which the entire steam demand is to be supplied.

In initiating operation of the system shown in Fig. 1 it may be interesting to note that, should manual valves 42, 45 and 5! be opened with main valve I5 remaining closed, a supply be delivered through pipe 44 from jet booster ceiver.

nozzle 49 to main supply pipe [9. Any flash steam in the receiver 21 will be circulated with the high pressure steam fraction delivered'by the jet booster nozzle 49 to and through the steam kettles l0, In with condensation in the latter during warmup thereof. If there is not sufiicient heat transfer in the steam kettles to condense this steam rapidly enough to reduce the pressure to the maximum dictated by safety valve 22, the latter may open and allow escape to atmosphere of enough steam to reduce the pressure to the predetermined maximum. That which does not escape through the safety relief valve 22 will be recirculated with collection of condensate in receiver 21. With loading of the kettles l0, It! the rate of condensation and the amount of condensate will increase with accompanying decrease in recirculation of steam, ultimately resulting in complete condensation of all the steam in the system accompanied by a drop in the pressure on the discharge side of the jet booster 43 to near atmospheric pressure or the pressure at drain 38. Then, if main steam valve 15 is opened, the pressure in main feed line l9 would rapidly build back up to about forty-five pounds (45 lbs.) gauge, and the apparatus would then automatically operate in the manner indicated above for complete operation of all components, with air-venting and condensate drainage from the receiver 21, and withdrawal bysuction of the flash steam from the receiver for recirculation due to the difierential of about seven pounds ('7 lbs.) gauge between the pressure in the receiver and in the main feed line.

The baffle means comprising staggered bailie plates Nit-I68 in Fig. 3 perform the functioning of perforated bafile plate 68 in Fig. l, and in a similar manner when used in lieu thereof. Air below such bafile means is made relatively quiet during the spilling of condensate down into the bottom of the receiver, thereby avoiding such turbulence as might cause mixing of the air with incoming flash steam and resulting carry-off therewith for circulation through the system.

In an embodiment of the system of Fig. 1 in a certain plant, wherein the heat transfer equipment was in the form of rotary steam tube dryers, there was available for the main supply of steam demand the exhaust from a steam turbine at a pressure of about forty pounds (40 lbs.) gauge. This steam source was'connected directly to main supply pipe I! for heating the steam dryers. With such relatively low pressure a fraction of such steam diverted through jet booster nozzle pipe 50 would not create a suction sufficient to give a differential in pressure which would economically recirculate flash steam and causedesirable rapid drainage of condensate to the re- It was found, however, that the system could be efficiently operated on that exhaust steam supply with the employment of an auxiliary, relatively high pressure steam source of very small capacity of the order of one-half of I one percent /2%) of the total steam demand for operating the jet booster 43, with connection of the nozzle 49 of the latter to that small aux-.

iliary high pressuresource by a separate pipe.

It will thus be seen that the objects set forth above and those made apparent in the preceding description are efiiciently attained by practice of the present invention and, since certain changes maybe made in the above construction and difierent embodimentsof the invention could be made without departing from the scope thereof, it is intended that all matter contained in the above description or shown in the accompanying drawing shall be interpreted as illustrative and not in a limiting sense.

It is also to be understood that the following claims are intended to cover all of the generic and specific features of the invention herein described, and all statements of the scope of. the invention which, as a matter of language, might be said to fall therebetween.

Having described my invention, what I claim as new and desire to secureby Letters Patent, is:

l. A steam heating circulation system comprising, in combination, heat exchange equip ment having at least one steam passage extending therethrough, a relatively low pressure steam source, main supply pipe means connecting said steam source directly to the steam passage for supplying th major amount of steam demand thereto, receiver means for separating condensate from flash steam, unobstructed return pipe means connected between the steam passage and said receiver means freely to conduct at all times condensate from the former to the latter, drainage means connected to said receiver means for discharge of condensate from the latter, conduit means connecting the topoi said receiver means to said main supply pipe means for recirculation of flash steam, a small jet booster having a nozzle in said conduit means, a relatively high pressure steam source, and auxiliary supply pipe means connecting said relatively high pressure steam source to said jet nozzle to supply thereto a minor fraction of the steam demand and induce a pressure in saidreceiver means lower than that in said main supply pipe means.

2. A steam heating circulation system comprising, in combination, heat exchange equipment having at least one steam passage extending therethrough, a source of relatively low pressure steam, main'supply pipe means connecting said steam source to the steam passage for supplying the major amount of steam demand thereto at a relatively low pressure, receiver means for separating condensate from flash steam, unobstructed return pipe means connected between the steam passage and said receiver means freely to conduct at all times condensate from the former to the latter, drainage means connected to said receiver means for discharge of condensate from the latter, conduit means connecting the top of said receiver means to said main supply pipe means for recirculation of flash steam, a small jet booster having a nozzle in said conduit means, a source of relatively high pressure steam, valve means connected to said main supply pipe means for limiting pressure therein to a predetermined maximum intermediate said relatively high and relatively low steam pressures, and auxiliary supply pipe means connecting said second steam source to said jet nozzle to supply thereto a minor fraction of the steam demand at a pressure appreciably higher than that in said main supply pipe means to induce a pressure in said receiver means lower than that in said main supply pipe means.

3. A steam heating circulation system comprising, in combination, heat exchange equipment having at least one steam passage extendlng therethrough, main supply pipe means connected directly'to the steam passage for supplying the major amount of steam demand thereto at a relatively low pressure, receiver means for separating condensate and flash steam from each other, said receiver means having an inlet communicating With its interior between the-top and bottom thereof, unobstructed return pipe means connecting the steam passage to the inlet of said receiver means freely to conduct at all times condensate from the former to said receiver means, conduit means connecting the top of said receiver means to said main supply pipe means for recirculation of flash steam, a small jet booster having a nozzle in said conduit means, auxiliary supply pipe means connected to said jet nozzle to supply thereto a minor fraction of the steam demand at a pressure appreciably higher than that insaid main supply pipe means, valve means connected to said main supply pipe means for limiting pressure therein to a predetermined maximum intermediate said relatively low pressure and said higher pressure, means providing for drainage of condensate from the bottom of said receiver means, automatic valve means controlling said drainage means and limitin maximum collection of condensate in said receiver means to a height appreciably below the inlet, automatic air-venting means having an intake communicating with the interior of said receiver means above but in the near vicinity of the maximum condensate collection height, and baifie means pervious to fluid in said receiver means below the inlet but appreciably above the venting intake to define therebetween a quieting zone for gaseous medium.

4. A steam heating circulation system comprising, in combination, heat exchange equipment having at least one steam passage extending therethrough, main supply pipe means connected directly to the steam passage for supplying the major amount of steam demand thereto at a relatively low pressure, receiver means for separating condensate and flash steam from each other, said receiver means having an inlet communicating with its interior between the top and bottom thereof, unobstructed return pipe means connecting the steam passage to the inlet of said receiver means freely to conduct at all times condensate from the former to said receiver means, conduit connecting the top of said receiver means to said main supply pipe means for recirculation of flash steam, a small jet booster having a nozzle in said conduit means, auxiliary supply pipe means connected to said jet nozzle to supply thereto a minor fraction of the steam demand at a pressure appreciably higher than that in said main supply pipe means, valve means connected to said main supply pipe means for limiting pressure therein to a predetermined maximum intermediate said relatively low pressure and said higher pressure, means providing for drainage of condensate from the bottom 01' said receiver means, automatic valve means controlling sald drainage means and limiting maximum collection of condensate in said receiver means to height appreciably below the inlet, air-venting means having an intake communicatin with the interior of said receiver means above but in the near vicinity of the maximum condensate collection height, a thermostatic valve controlling the outlet of said air-venting means, and bafiie means pervious to fluid in said receiver means below the inlet but appreciably above the venting intake to define therebetween a quiethig zone for gaseous medium.

5. A steam heating circulation system comprising, in combination, heat exchange equipment having at least one steam passage extending therethrough, main supply pipe means connected directly to the steam passage for supplying the major amount of steam demand thereto at a relatively low pressure, a closed receiver tank of appreciable height for separating condensate and flash steam from each other, means forming an inlet to the interior of said tank at a point appreciably below the top thereof, a steam zone of appreciable dimension adjacent said inlet and appreciably above the bottom thereof to provide for a lower condensate collection zone and an intermediate zone, unobstructed return pipe means connecting'the steam passage to thetank inlet means freely to -conduct at all times condensate from the former to said tank, conduit means connecting the steam zone in the top of said tank to said main supply pipe means for recirculation of flash steam, a small jet booster having a nozzle in said conduit means, auxiliary supply pipe means connected to said jet nozzle to supply thereto a minor fraction of the steam demand at a pressure appreciably higher than that in said main supply pipe means, valve means connected to saidmain supply pipe means for limiting pressure therein to a predetermined maximum intermediate said relatively low pressure and said hgher pressure, means providing for drainage of condensate from the bottom of said tank, automatic valve means controlling said drainage means and limiting maximum collection of condensate-in the bottomof said tank to a height defining the top of the condensate zone, baffle means pervious to fluid in said tank below the tank inlet means to define between it and the condensate 'zone the intermediate zone and to assure quietingof air in the latter zone, air-venting means having an intake communicating with the interior of said tank above but in the near vicinity of the top of the condensate zone, and a thermostatic valve controlling the outlet of said air-venting means.

6. A condensate receiver for installation in a steam heating circulation system, comprising a closed tank of appreciable height for separating condensate and flash steam from each other, means forming a condensate return inlet to the interior of said tank at a point appreciably below the top and appreciably above the bottom thereof, a steam zone of appreciable dimension in the top of said tank adjacent said condensate return inlet, an intermediate zone below said steam zone, a condensate collection zone below said intermediate zone, means for connecting the steam zone in the top of said tank to a flash steamConduit for recirculation of flash steam, means providing for drainage of condensate from the bottom of said tank, automatic valve means to control said drainage means and limit maximum collection of condensate in the bottom of said tank to a height defining the top of the condensate zone, bafile meanspe'rvi'ous to fluid in said tank belowthe tank' inlet means to define between it and the condensate zone the intermediate zone'and toassure quieting of air in the latter zone, and air-venting means having an intake communicating with the interior of said tank above but in the near vicinity of the top of the condensate zone.

'7. A condensate receiver for installation in a steam heating circulation system, comprising a closed tank of appreciable height for separating condensate and flash steam from each other, means forming a condensate return inlet to the interior of said tank at a point appreciably below the top and appreciably above the bottom thereof, a steam zone of appreciable dimension in the top of'said tank adjacent said condensate return inlet, an intermediate zone below said steam zone, a condensate collection zone below said intermediate zone, means for connecting the steam zone in the top of said tank to a flash steam conduit for recirculation of flash steam, means providing for drainage of condensate from the bottom of said tank, automatic valve means to control said drainage means and limit maximum collection of condensate in the bottom of said tank to a height defining the top of the condensate zone, baffie means pervious to fluid in said tank below the tank inlet means to define between it and the condensate zone the intermediate zone and to assure quieting of air in the latter zone, air-venting means having an intake communicating with the interior of said tank above but in the near vicinity of the top of the condensate zone, and valve means in said airventing means selectively to pass air at temperatures appreciably-below that of flash steam and to bar passage of flash steam. 7

8. A condensate'rec'eiver for installation in a steam heating circulation system, comprising a closed tank of appreciable height for separating condensate and flash steam from each other, means forming a condensate return inlet to the interior of said tank at a point appreciably below the top and appreciably above the bottom thereof, a steam zone of appreciable dimension in the top of said tank adjacent said condensate return inlet, an intermediate zone below said steam zone, a condensate collection zone below said inter- -mediate zone, means for connecting the steam zone in the top of said tank to a flash steam conduit for recirculation of flash steam, means providing for drainage of condensate from the bot-' tom of said tank, automatic valve means to control said drainage means and limit maximum collection of condensate in the bottom of said tank to a height defining the top of the condensate zone, bafile means pervious to fluid in said tank below the tank inlet means to define between it andthe condensate zone the intermediate zone and to assure quieting of air in the latter zone. air-venting means having an intake communicating with the interior of said tank above but in the near vicinity of the top of the condensate therein above a predetermined maximum, said predetermined maximum being greater than said operating pressure and lower than said higher pressure,receivermeanshaving a steam zone and a condensate collection zone, return pipe means connecting said steam passage and said receiver means for conducting steam and condensate from the former to the latter, valve means connected to said condensate collection zone for discharge of condensate therefrom, conduit means connecting said steam zone and said main supply pipe means, and means connected into said conduit means, including means for receiving steam from said source at higher than said operating pressure, for utilizing said received steam for inducing a flow of steam from said steam zone through said conduit means and thereby maintaining said receiver means at lower than said operating pressure means for admixing said received steam and said steam from said steam zone and thereby providing a mixture of steam substantially at said operating pressure, and means for introducing said mixture of steam into said main supply pipe means for admixture with steam from said source at operating pressure.

10. In a steam heating circulation system comprising a main steam supply pipe for conducting steam at operating pressure, heat exchange equipment having at least one steam passage therethrough, a return pipe, and a receiver, in combination, a primary source or steam at operating pressure, means connecting said source with said main steam supply pipe, a secondary source of steam at substantially greater than said operating pressure, nieansfor employing steam fromsaid secondary source for maintaining said receiver at lower than said operating pressure including means for withdrawing flash steam from said receiver and mixing the same with said steam from said secondary source whereby to provide a steam mixture substantially at said operating pressure, and means for introducing said mixture into said main steam supply pipe for admixture with steam from said primary source.

11. A steam heating circulation system comprising a supply main for conducting steam at relatively high pressure, a reducing valve connected to the supply main for reducing steam from relatively high pressure to relatively intermediate pressure, a distributing main-connected to the reducing valve for conducting steam at said relatively intermediate pressure, heat exchange equipment having a passage therethrough connected to the distributing main for receiving said steam at relatively intermediate pressure and converting at least a portion thereof into condensate, a return pipe connected to the passage in the heat exchange equipment for conducting condensate, a receiver connected to the return pipe for receiving condensate, conduit means connected between the receiver and the distributing main, a feed pipe connected between the supply main and said conduit means for conducting steam at relatively high pressure to the latter, and means in said conduit means for employing said relatively high pressure steam conducted thereto to maintain a relatively low pressure in the receiver whereby at least a portion of said condensate may be converted into steam at said relatively low pressure, said means being further effective to Withdraw said relatively low pressure steam from the receiver, to mix the same with said relatively high pressure steam conducted to the conduit means thereby producing steam substantially at said relatively intermediate pressure, and to inject the same into the distributing main.

12. In a steam heating system, a first source of steam at a predetermined moderate pressure, a second source of steam at a predetermined higher pressure, heat exchange means for usefully absorbing heat from steam at the predetermined moderate pressure thereby converting the same to condensate, means for conducting steam from said first source to the heat exchange means, receiving means for receiving condensate, means for conducting condensate to the receiver means, a vapor space in the receiver means for the formation of flash steam therein, automatic drainage means in thereceiver means for draining excess condensate therefrom and thus maintaining said vapor space therein, and means including jet means for withdrawing flash steam from the receiver, augmenting the same with steam from said second source, and injecting the same into the aforementioned means for conducting steam from said first source to the heat exchange means.

13. In a steam heating system, a first source of steam at a predetermined moderate pressure, a second source of steam at a predetermined higher pressure, heat exchange means for usefully absorbing heat from steam at the predetermined moderate pressure thereby converting the same to condensate, means for conducting steam from said first source to the heat exchange means, receiving means for receiving condensate, means for conducting condensate to the receiver means, a vapor space in the receiver means for the for mation of flash steam therein, automatic drainage means in the receiver means for draining excess condensate therefrom and thus maintaining said vapor space therein, and combination means including jet means employing steam from said second source for maintaining said vapor space at a sufliciently low pressure to permit at least a portion of the condensate in the receiver to flash into steam, said combination means further including means for withdrawing flash steam from the receiver, mixing the same with steam from said second source, and injecting the mixture into the aforementioned means for conducting steam from said first source to the heat exchange means.

BRONSON C. SKINNER.

References Cited in the file of this patent UNITED STATES PATENTS Number Name Date 1,619,662 Field 1 Mar. 1, 1927 1,692,682 Montreuil Nov. 20, 1928 1,722,847 Jennings July 30, 1929 1,806,304 Miersbe May 19, 1931 1,897,398 Raymond Feb. 14, 1933 1,916,073 Rosenblad June 27, 1933 1,968,171 Reiss et a1 July 31, 1934 1,969,181 Miersbe Aug. 7, 1934 2,091,801 Amick et a1. Aug. 31, 1937' 2,223,407 Dean Dec. 3, 1940 

